There is nothing in written British law barring the current monarch Queen Elizabeth II from voting in an election. But, as the Brits might say, it just isn’t done. “Although not prohibited by law,” the U.K. parliament website says, “it is considered unconstitutional for the Monarch to vote in an election.”

The queen does, however, play a formal role in the country’s political process: The day after the election, she will invite the leader of the party with the most seats to form a government. Assuming that person can command a majority (made of either their own party or a coalition), he or she then becomes prime minister.

The queen’s ceremonial role as head of state means that she signs all bills into law, meets with foreign dignitaries and performs other duties. It’s a position that brings huge potential influence without accountability to voters, and means her political neutrality is considered vital.

In recent years, the palace has furiously denied several claims that the monarch had expressed political views.

During the Brexit referendum of 2016, British tabloid The Sun reported that she had expressed anti-EU views at a dinner, an allegation rejected by her staff. Buckingham Palace complained to Britain’s press regulator, saying that the paper’s headline “Queen backs Brexit” was inaccurate. (The regulator upheld the palace’s complaint and The Sun had to publish a correction.)

In the run-up to the 2014 Scottish Independence referendum, the Queen told a well-wisher near her Scottish estate: “Well, I hope people will think very carefully about the future” before the vote. The palace denied this was a political intervention, but it was taken by some pro-U.K. campaigners as an endorsement of their cause.

The rules governing royals beyond the queen are less firm. But a Buckingham Palace spokesperson tells Newsweek that “by convention,” members of the royal family “close to the queen” do not exercise their right to vote.

The spokesperson would not confirm how many royals that covers, but said it would include “senior members” of the royal family such as Prince William, the Duke of Cambridge, and Kate Middleton, the Duchess of Cambridge.

And, just like the Queen, senior royals are expected to stay politically neutral in public, though the media often tries to tease out their views.

Prince Charles, the queen’s son and next in line to the throne, came under heavy scrutiny in 2015 after British media released letters he had written to government ministers, gained via a freedom of information request. Critics said he was seeking to lobby the government on contentious issues such as alternative medicine.

And Prince William, Charles’s son and second in line to the throne, told diplomats months before the European Union referendum that, “In an increasingly turbulent world, our ability to unite in common action with other nations is essential. It is the bedrock of our security and prosperity and is central to your work.”

But his office insisted that William was not referring to Europe or the EU, and that stressing the importance of cooperation did not amount to expressing a political view.

In the event, Britons voted to leave the EU, and for whoever wins on Thursday negotiating the U.K.’s exit from the bloc will be the biggest task they face.